DE102010023855A1 - Method for manufacturing metallic valve housing by internal high pressure forming of pipe section in tool, involves inserting pipe section into mold filled with liquid, where internal high-pressure is applied to pipe section - Google Patents

Abstract

The method involves inserting a pipe section (10) into a mold (40) filled with a liquid. An internal high-pressure is applied to the pipe section. Opposing walls of the pipe section are shaped in a middle section (110) lying between two pipe ends (100). A side of the pipe section is pressed by punching under formation of a concave curve.

Description

The invention relates to a method for producing a metallic valve housing.

From the EP 0 726 103 a method for the production of metallic valve housings is known in which, starting from a pipe section, a valve housing is produced by means of forming technology. The pipe section is filled with a plastic material, in particular wax, closed at its ends by sealing plugs and deformed by the action of an external force from a punch. The resulting internal pressure presses the wall of the deformed pipe section to an outer shape, whereby the contour of the valve housing is formed.

In this method, it has been found that the tolerances of the valve housing thus produced are highly dependent on the amount of filled wax. Even small fluctuations in the amount of filling material have a strong effect on the internal pressure generated in the pipe section, which means that it is not guaranteed that the wall of the pipe section always adapts completely to the contour of the outer shape.

Even if the known method over the then prior art, such as the production as a cast or forged housing, already offers great advantages, it is still consuming and contains many process steps that must be performed sequentially: The pipe section is filled with wax , which is melted out after the forming process. Subsequently, a cleaning step is necessary. Due to the dimensional variations, the outer diameter of the opening produced in the deformed pipe section must be over-turned, which serves as a connection interface for a drive in the finished valve housing.

It is therefore an object of the invention to improve the known method for the production of metallic valve housings so that a number of process steps can be saved, so the efficiency is increased, and very tight tolerances can be adhered to the finished housings.

Starting from the in the EP 0 726 103 described method, the invention provides a method for producing a valve housing according to claim 1.

In a method according to the invention, a pipe section is first introduced into a tool with upper and lower part, wherein the upper part has a punch and the lower part has a depression. Subsequently, the pipe section is filled with a liquid and subjected to internal high pressure. Then, the punch is pressed transversely to the axis of the pipe section in a lying between two pipe ends central portion inwardly, almost to the opposite wall, so that forms a concave curvature corresponding to the punch shape. At the same time the wall opposite this is pressed by the internal high pressure to the depression in the lower tool part to form a flattening. The invention is based on the idea of not generating the internal pressure necessary for forming "passively" by inserting the punch, but actively by pressurizing the interior of the tube with high pressure before the punch is inserted. Due to the high internal pressure, which is used in the manufacturing process of the valve housing according to the invention, it is advantageously ensured that the original wall of the pipe section completely adapts to the contour of the punch and the tool, which ensures the desired high tolerance accuracy. After separation of the flattening, in particular the formed breakthrough of the valve housing blank has an inner diameter with a very exact dimensional accuracy.

While the pipe section undergoes such a strong deformation in its central region that nothing is retained here about the original pipe geometry, the shape of the pipe ends is not changed.

The pipe section can also be additionally formed in the region of the tube ends by means of internal high pressure. For this purpose, corresponding further depressions are then arranged in the tool upper and lower part.

The metallic Ventilgehäuserohling thus prepared is further processed in a known manner: the flattening is separated to form a breakthrough, the standing annular collar crimped around a flange, and then the flange and collar are joined together by welding.

In the finished valve housing, the pipe ends serve as Fluidein- and output and the concave curvature serves as a threshold and valve seat, which separates them from each other. With an open valve, fluid inlet and outlet are interconnected, and fluid can flow from the fluid inlet via the threshold to the fluid outlet.

As far as designations such as "top" and "bottom" are used to describe the method and the tool, this serves for a clearer and clearer explanation and is not meant to be limiting. The procedure works in in the same way, when the punch is arranged in the lower part and the depression in the upper part, or the tool has a different spatial position.

In the hydroforming method used here, water, oil or a water / oil mixture is frequently used as the liquid for filling the part to be formed. Typical internal high pressures range between 1000 and 6000 bar. For large internal diameter pipe sections, lower pressures are required, and for smaller internal diameter pipe sections, higher pressures must be provided for this process.

In an advantageous variant of the method, the depression in the tool lower part along its circumference has a step for receiving a flange. During the forming process, the hydroforming pushes the wall of the pipe section adjacent to the flange through the flange, forming an annular collar that forms a positive connection with the flange. This has the particular advantage that the connection between collar and flange has virtually no gap, which facilitates the subsequent necessary welding process and also significantly increases the quality of welding at the junction.

In a further development of the method according to the invention for producing valve housings, following the connection of flange and pipe section, the flattening is effected by the action of an external radial force in the direction. pressed to the pipe section central axis. As a result, the annular collar is flanged and settles around the flange.

All of the manufacturing steps described above advantageously take place in a single tool. As a result, several steps can be saved because the tube section to be formed does not have to be removed from a tool and then inserted into one or more other tools, which would require a careful positioning of the workpiece each time.

In a further variant of the method, the tool lower part has a transverse to the axis of the pipe section separating plate, in which the depression is arranged. With rapid displacement of the partition plate to the outside and simultaneously maintaining the internal high pressure, the flattening is blasted off, and the breakthrough is formed. This has the advantage that a further production step can be carried out in the same tool and the flattening does not have to be separated separately, for example by means of milling. This means that the pipe section is inserted into the tool, several process steps are automatically carried out there using known machine control technology, and the valve housing blank with flange, flanged collar and already formed opening can be removed. To complete the valve housing so only the welding or soldering process is required. In this way, the entire production process for metallic valve housing can be considerably simplified.

In a preferred variant of the method, the tool lower part has a sharp edge on its inner wall, against which the annular collar rests, in the parting plane to the partition plate. This has the advantage that the extent of the breakthrough, which arises when blowing off the flattening, has a clean and uniform contour. The sharp edge may alternatively be arranged at the peripheral edge of the recess in the partition plate.

It has proven to be advantageous to provide the pipe ends of the tube section to be formed in the tool with pressure connections, which have a channel. This channel is used to fill the pipe section with liquid and pressurization or for venting.

In a further variant of the method, the pressure connections on the opposite side of the pipe ends have a conical geometry and enter into a frictional connection with the pipe ends. This has the advantage that no extra sealing element and thus no wear-prone part is needed.

The tapered pressure ports may be advanced during the forming process as the tube ends move toward the punch. As a result, the pipe section material flows, thereby forming uniform wall thicknesses in the valve housing.

The application of this sealing principle by means of conical sealing connections is possible in a very large pressure range and even works at extremely high pressures, as required for forming pipe sections with small diameters. With "small" diameters here are in particular nominal diameters from / to DN 25 meant.

As an alternative sealing principle for sealing the pressure connections with the pipe ends radial sealing elements are used. The pressure connections are pushed into both pipe ends and held by support plates, which are anchored in the upper tool and enter into a locking connection with the lower tool part. In this case, the material of the pipe section flows during the forming process, without the pressure connections be postponed. This sealing principle is limited to a limited pressure range and can not be used in particular for forming pipe sections with small diameters.

As a particularly suitable material of the pipe section has been found for the inventive production method of metallic valve bodies stainless steel. But it can also be used other metallic materials.

Further features and advantages of the invention will become apparent from the following description and from the accompanying drawings, to which reference is made. In the drawings show:

1 a sectional view of a pipe section in a tool for a method according to the invention;

2 a sectional view of a deformed pipe section in the tool;

2a a sectional drawing of a Ventilgehäuserohlings made according to 1 and 2 ;

3 a sectional view of a deformed pipe section in the tool for a process variant;

3a a sectional drawing of a Ventilgehäuserohlings made according to 3 ;

4 a sectional drawing of a deformed pipe section for a process variant in the closed tool;

5 a further sectional view of a deformed pipe section for the process variant according to 4 in a closed mold;

6 a sectional drawing of a formed pipe section for a process variant according to 4 and 5 with the tool open;

6a a sectional drawing of a Ventilgehäuserohlings made according to 4 - 6 ;

6b further sectional drawing of the valve housing blank made according to 4 - 6 ;

7 a sectional drawing of a pipe section in the open tool for a further process variant;

8th a sectional view of a pipe section in the open tool according to 7 in which the pressure connections are retracted into the pipe section;

9 a further sectional drawing of a pipe section in the closed tool according to 7 and 8th in which the pipe section has not yet been reshaped;

10 a further sectional drawing of a deformed pipe section in the tool according to 7 . 8th and 9 ;

11 a cross-sectional view of a formed pipe section for a further process variant;

12 a sectional view of a deformed pipe section according to the process variant according to 11 in a subsequent process step; and

13 a further sectional drawing of a deformed pipe section according to the process variant according to 11 in a final process step.

1 shows you in a tool 20 inserted pipe section 10 , The tool 20 has a top 30 with stamp 40 , a lower part 50 with a sink 60 and an ejector 70 , as well as two pressure connections 80 with one channel each 90 on. The pressure connections 80 be at the pipe ends 100 of the pipe section 10 connected and through the channel 90 with a liquid, in particular water or a water / oil mixture, filled and pressurized. The pressure connections 80 point to the pipe ends 100 opposite sides of a conical geometry and go with the pipe ends 100 a non-positive connection, as in 2 shown. The conical pressure connections 80 can during the forming process when the pipe ends 100 to be moved in the direction of the punch, to be pushed. As a result, the pipe section material flows, which advantageously form uniform wall thicknesses in the valve housing. Due to the conical geometry of the pressure connections 80 can be achieved without the use of an additional seal the sealing of the internal high pressure. With this sealing principle, a reliable seal can be achieved over a wide pressure range. It can even pipe sections with nominal widths below DN 25 which requires pressures around 6000 bar.

The Stamp 40 is according to 2 transverse to the axis of the pipe section 10 in its middle section 110 pressed inwards, so that the stamp 40 opposite wall of the pipe section 10 the contour of the stamp 40 adapts and a concave curvature 120 formed. On the opposite side is the wall of the pipe section 10 by means of the applied Internal high pressure in the depression 60 pressed and there forms the flattening 130 , It is particularly advantageous that very tight tolerances can be met, because the internal high pressure ensures that the wall of the original pipe section 10 after forming exactly the contour of the depression 60 maps. In this method, a very high process reliability can be ensured, since this is highly dependent on the internal high pressure, but which is easily adjustable.

The inventively prepared in 2a illustrated, Metallische Ventilgehäuserohling 140 is processed in a known way: the flattening 130 is separated to form a breakthrough and the standing collar 150 is crimped around a flange. Subsequently, ring collar 150 and flange welded or soldered together.

In contrast to 2 points in 3 the tool 20 in the lower part 50 along the circumference of the depression 60 a step 160 for receiving a flange 170 on. The sinking 60 opposite wall of the pipe section 10 is by means of hydroforming through the flange 170 through into the depression 60 for flattening 130 under formation of a positive connection of annular collar 150 and flange 170 pressed. As a result, a process step is saved and there is a virtually gap-free connection between collar 150 and flange 170 reached. Thus, the subsequently necessary welding process after separation of the flattening 130 simplified and the welded joint shows a significantly improved quality.

In the 4 to 6 is an evolution of the in 3 shown method shown.

4 shows the pipe section 10 in the tool 20 with top 30 and stamp 40 , Pressure connections 80 and channel 90 , Step 160 for receiving the flange 170 , as well as the lower part 50 , which is now a partition plate 180 which is transverse to the axis of the pipe section 10 is displaceable. In the partition plate 180 is the depression 60 arranged, which has a sharp edge at its peripheral edge 190 shows. As already described above, the wall of the pipe section also fits in this process variant 10 on one side of the contour of the stamp 40 on, and the opposite wall is pressed by means of internal high pressure down and out. In the further development, the wall is now through the flange 170 through into the depression 60 under formation of the flattening 130 pressed. With fast moving of the separating plate 180 A short distance to the outside, away from the pipe section, is according to 5 the flattening 130 along the sharp edge 190 blasted off. After opening the tool, shown in 6 , the Ventilgehäuserohling 140 be removed. This variant of the method has the advantage that a further production step can be carried out in the same tool. The usually necessary separation of the flattening 130 Milling is eliminated. The valve housing blank removed from the tool 140 already shows the breakthrough 200 on. The sharp edge 190 favors that the extent of the breakthrough 200 when blowing off the flattening 130 has a clean and even contour.

The 6a and b show sectional drawings of the valve housing blank 140 , which according to the method shown in the 4 - 6 , is made. The valve housing blank 140 has the concave curvature 120 on, this opposite the breakthrough 200 , the flange 170 and the ring collar 150 that with the flange 170 is positively connected.

In the 7 - 10 Another method variant is described, which is preferably applied at lower internal pressures. This process variant is above all for forming pipe sections with larger diameters and diameters over DN 25 suitable.

The pressure connections 80 have radial sealing elements 210 and get into the tube ends 100 pushed. The tool 20 includes a top 30 with stamp 40 and a lower part 50 with depression 60 and ejector 70 , top 30 and lower part 50 are between an upper base plate 220 and a lower base plate 230 arranged. The upper base plate 220 has two support plates 240 on.

The pipe section 10 with the pressure connections 80 is with the tool closed 20 between the support plates 240 arranged (see 10 ), these being in recesses 250 the lower base plate 230 penetration. In this case, the material of the pipe section flows 10 during the forming process, without the pressure connections 80 be postponed separately.

Of course, this process variant with radial sealing elements 210 on the pressure connections 80 also be applied to the methods where the flange 170 with the pipe section 10 in the tool 20 is connected, the annular collar 150 around the flange 170 is flattened or the flattening 130 is blown off.

In the 11 - 13 a variant of the method for the production of metallic valve housings is shown.

11 shows a deformed pipe section 10 in the tool 20 with top 30 and stamp 40 , as well as lower part 50 with a step 160 for receiving a flange 170 , The lower part 50 has a disc 260 and a closely surrounding support ring 270 on, both both individually and together across the axis of the pipe section 10 are displaceable. The support ring 270 lies with an end face 280 on the flange 170 on. The inner wall of the support ring 270 forms together with the pipe section 10 opposite side of the disc 260 the depression 60 by the disc 260 in relation to the support ring 270 something outward, away from the pipe section 10 , is moved.

The geometry of the Ventilgehäuserohlings initially formed in the same manner as described above, when moving the punch 40 transverse to the axis of the pipe section 10 and loading the pipe section 10 with hydroforming off. The sinking 60 opposite wall of the pipe section 10 is through the flange 170 through into the depression 60 under formation of the flattening 130 and the ring collar 150 pressed. The support ring 270 prevents uncontrolled forming of the pipe section 10 in the bottom area of the flattening 130 ,

According to 12 then the support ring 270 transverse to the axis of the pipe section 10 outward, away from the flange 170 , moved until the end face 280 of the support ring 270 leading to the flange 170 is adjacent, with the pipe section 10 pointing side of the disc 260 forming a plane.

Then the flattening 130 , as in 13 shown by means of the support ring 270 and the disc 260 radially inward towards the pipe section axis until it rests against the flange 170 pressed. This will make the waistband 150 flanged and lays around the flange 170 , In a further method step, as described above, the flattening 130 be blown off. In this case, the sharp edge can also be arranged on the end face of the flange.

The inventive method and the method variants for the production of valve housings are particularly suitable for forming by means of internal high pressure of stainless steel pipe sections. But it can also be used pipe sections of other metallic materials.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0726103 [0002, 0006]

Cited non-patent literature

• DN 25 [0022]
• DN 25 [0043]
• DN 25 [0050]

Claims (11)

A method for producing a metallic valve housing by hydroforming a pipe section in a tool having a top having a punch, a lower part having a recess, wherein the pipe section is introduced into the tool, filled with a liquid and subjected to internal high pressure and opposite walls of the tube section are deformed in a middle section lying between two tube ends by pressing one side of the tube section inwards transversely to the axis of the tube section by means of the punch, forming a concave curvature and the opposite wall into the depression in the lower part to form a flattening. A method of manufacturing a metal valve housing as claimed in claim 1, wherein the recess in the tool base has a step for receiving a flange along its periphery, pushing the wall of the pipe section adjacent to the flange into the recess to form a collar through the flange and the annular collar with the flange enters into a positive connection. A method of manufacturing a metal valve housing according to claim 2, wherein the flattening in the tool is forced by the action of an external radial force towards the central axis of the pipe section, thereby crimping the collar and laying around the flange. A method for producing a metallic valve housing according to claims 1 to 3, wherein the tool lower part has a transverse to the axis of the pipe section movable separating plate, in which the depression is arranged, whereby at rapid displacement while maintaining the internal high pressure, the flattening is blasted off. A method for producing a metallic valve housing according to claim 4, wherein the lower tool part has on its inner wall, against which the annular collar, in the parting plane to the partition plate has a sharp edge. Method for producing a metal valve housing according to one of the preceding claims, wherein pressure connections are connected at both ends of the pipe in its extension, having a channel for supplying liquid and pressurizing or venting. Method for producing a metal valve housing according to claim 6, wherein the pressure ports on the opposite sides of the pipe ends have a conical geometry and form a frictional connection with the pipe ends. A method for producing a metallic valve housing according to claim 6 or 7, wherein the pressure ports are nachgeschoben during the forming process in the direction of pipe section in flow of the pipe section material. A method for producing a metallic valve housing according to claim 6, wherein the pressure connections are retracted in both pipe ends and sealed there by means of radial sealing elements. A method for producing a metallic valve housing according to claim 9, wherein the pressure ports are held in the retracted position of support plates which are anchored in the upper tool and enter into a snap-in connection with the lower tool part. Method for producing a metallic valve housing according to one of the preceding claims, wherein the pipe section is made of stainless steel.

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